喀斯特槽谷区岩石与坡面夹角对产流产沙过程的影响

Effects of Angle Between Rock and Slope on the Processes of Runoff and Sediment Yield in the Karst Trough Valley Area

为明确喀斯特槽谷区岩石与坡面夹角对坡面产流产沙过程的影响,在6个岩石与坡面夹角(30°,60°,90°,120°,150°,180°)、3个坡度(10°,15°,20°)和3个流量(5,7.5,10 L/min)组合条件下,开展室内放水冲刷试验。结果表明:(1)地表产流率随冲刷历时呈先增加后稳定的趋势,而含沙量和地表产沙率随冲刷历时均呈波动性减小趋势;(2)各岩石与坡面夹角下,地表产流率无显著差异(P>0.05);但含沙量与地表产沙率均差异显著(P<0.05),表现为含沙量和地表产沙率在60°夹角下与30°和120°夹角下差异不显著(P>0.05),但显著高于90°,150°和180°条件下的含沙量和地表产沙率(P<0.05);(3)地表产流率与含沙量在60°,90°,120°夹角下均呈显著幂函数正相关(R^(2)=0.32~0.56,P<0.05),而在其他夹角下二者关系不显著(P>0.05)。地表产流率与地表产沙率在60°,90°,120°,150°,180°夹角下呈显著线性正相关(R^(2)=0.35~0.86,P<0.05)。研究表明喀斯特槽谷区岩石与坡面呈一定夹角时,可加剧坡面产沙,并改变产流与产沙关系。

To elucidate the roles of angle between rock and slope in affecting the processes of runoff and sediment yield in the Karst Trough Valley Area of Southwest China,the combined conditions of 6 angles between rock and slope(30°,60°,90°,120°,150°,180°),3 slope gradients(10°,15°,20°),and 3 flow rates(5,7.5,10 L/min)were employed in laboratory scouring simulation experiments.Results showed that:(1)Surface runoff rate increased to be stable with scouring duration,while sediment concentration and sediment yield rate both increased first and then decreased with the scouring duration;(2)Surface runoff rate showed non-significant differences among different angles between rock and slope(P>0.05).Sediment concentration and sediment yield both displayed non-significant differences among the angels of 30°,60°and 120°(P>0.05),which were significant higher than those angels of 90°,150°and 180°(P<0.05);(3)Surface runoff rate presented significantly positive power relationships with sediment concentration under the angles of 60°,90°and 120°(R^(2)=0.32~0.56,P<0.05),while exhibited non-significant relationships with sediment concentration at other angles(P>0.05).Similarly,surface runoff rate was significantly linearly correlated with sediment yield at the angles of 60°,90°,120°,150°and 180°(R^(2)=0.35~0.86,P<0.05).Our results show that a certain angle between rock and slope in the slope of the Karst Trough Valley area can accelerate the sediment yield and change the relationship between runoff and sediment yield.